"They were one of the first of the Oregon National Guard to go over to Iraq and they actually worked on what is called the IED corridor," said Brain Injury Association of Oregon Executive Director Sherry Stock. "They were in transportation and these guys were mortared or setting off IEDs every day."

During Bravo Company's 15 month deployment, they lived through massive IED explosions and mortar attacks on a daily basis. These blasts can send sound waves hurtling though the air at 1,600 feet per second, sending percussion waves through the heads of soldiers.

"The first time it gets you," said Bravo Company's Julio Najara, "the first time you're like oh my God. You're like -- you freeze."

"Brain injury and war go hand in hand," said Stock. "The percussion waves are so great they're throwing vehicles, throwing people as well as shrapnel."

Brain injury specialists say when shock waves from the blast travel through the heads of soldiers, tiny air bubbles are created in the brain tissue. And doctors say those bubbles can spontaneously pop even several months after an explosion.

"People without real serious looking wounds end up dying or nearly dying from blast wave exposure," said Oregon National Guard Major James Sardo. "The problem with TBI is that it's an internal injury, and someone could be seriously injured and look just fine."

Of the 1.6 million soldiers who have fought in Iraq and Afghanistan, it's estimated that 320,000 - or one in every five soldiers - came home brain injured.

"They're as smart as they ever were but it's much more effortful to do the same things they used to," said Sardo. "To sit down and read a chapter they may have to stop 10 to 15 minutes to rest."

Adjusting to life back at home isn't easy for guardsmen. In fact, some say life would be less complicated back in the war zone.

"I would surely do it over again if I had to," said Najara. "I wouldn't think about it. In fact I think life would be easier sometimes if I went back over there."